// DC Voltage Module with Datalogger Shield By Solarduino

// 1 - DC Voltage Measurement

int analogInputPin = A2;
float vArduino = 0.0;
float vActual = 0.0;
float R1 = 30000.0;
float R2 = 7500.0;
int rawValueRead= 0;

// 2 - Data Logger shield

#include<Wire.h>
#include "RTClib.h" // Must download the library from manage library > type RTCLib by Adafruit
#include<SPI.h>
#include<SD.h>

RTC_DS1307 RTC;
DateTime now;

int chipSelect = 10;

File mySensorData;
unsigned long startMillisSD;
unsigned long currentMillisSD;
const unsigned long periodSD = 5000;

void setup()
{

// 1 - DC Voltage Measurement

pinMode(analogInputPin, INPUT);
Serial.begin(9600);
Serial.println("DC VOLTMETER");

// 2 - Data Logger shield

pinMode(chipSelect,OUTPUT);
RTC.begin();
Wire.begin();
SD.begin(chipSelect);
startMillisSD = millis();
RTC.adjust(DateTime(F(__DATE__), F(__TIME__)));
if(! RTC.isrunning())
{
Serial.println("RTC is not running !");
}

}

void loop()

{
// 1 - DC Voltage Measurement

rawValueRead = analogRead(analogInputPin);
vArduino = (rawValueRead * 5.0) / 1024.0;
vActual = vArduino / (R2/(R1+R2));

Serial.print("Vdc = ");
Serial.println(vActual,2);
delay(1000);

// 2 - Data Logger shield

currentMillisSD = millis();
if (currentMillisSD - startMillisSD >= periodSD)
{
mySensorData=SD.open("SOLARD.txt",FILE_WRITE);
if(mySensorData)
{
DateTime now = RTC.now();
mySensorData.print(now.year(),DEC);
mySensorData.print("/");
mySensorData.print(now.month(),DEC);
mySensorData.print("/");
mySensorData.print(now.day(),DEC);
mySensorData.print(" ");
mySensorData.print(now.hour(),DEC);
mySensorData.print(":");
mySensorData.print(now.minute(),DEC);
mySensorData.print(":");
mySensorData.print(now.second(),DEC);
mySensorData.print(",");

mySensorData.println(vActual,2);

mySensorData.close();
Serial.println("written to SD Card !");
startMillisSD = currentMillisSD ;
}
}

}